[X] Pay careful attention to their emotional states. Their moods, their highs and lows. Put what you know about humans to the test, and learn more besides. Exhaustive notes about their temperaments can only be an asset.
[x] Study them intently for likes and dislikes, then wait for the right moment to strike. Ruby said something about sharing an affinity for books with regards to Belladonna - if you pick your moment carefully, such a tactic can't possibly fail.